I don't know much about computer which used these
boards. I got them many years ago from Agricultural University and they
probably got them from Jagiellonian University in Cracow. Modules are
populated with TTL chips, Soviet equivalents of western 74xx series.
These chips have been manufactured by many plants in USSR, some of them
manufactured only small batches of chips in late 1970s (see "EC" and
"lightbulb" logo). Most chips are from 1978 and 1979.
One of boards seems to be "patched" with wires, so the computer was
serviced. Stamps on boards are typical quality control stamps, date from
1979 and OTK stamp (meaning that device complies to military
specifications, but these specifications are very different in quality -
It's Soviet Union, they used not the best hardware, but the most
accessible one!).
Boards can be configured using soldered jumpers. All of them have rack
latches on one side and edge connectors on the other.

In Agricultural University I've also seen modules with
2 edge connectors, located 90 degrees from each other (on 2 sides of
square PCB).

Manufacturer

???

Origin

Soviet Union

Year of unit

late 1970s

Year of introduction

??

Type

Parts of ?computer?

If you are curious or want to reverse-engineer something,
here are high-resolution scans of these boards: